In a conventional rotary apparatus, if a rotary shaft rotates at a high speed, it is necessary to use a special bearing which is appropriate for high-speed rotation. When the rotary shaft rotates at a high speed, the bearing receives a large load. Therefore, it is expected to improve stability and lifetime of the bearing.
In Japanese Patent Unexamined Publication No. 2000-271804, the present applicant proposed a rotary apparatus allowing high-speed rotation of a rotary shaft without much loading against a bearing, even if the bearing has a low peripheral speed condition.
If the load applied on the bearing is imbalanced, however, backlash of the gear or increment of friction sometimes causes a trouble on rotation.
On the other hand, lubricant for the bearing should be appropriately used in view with a configuration of a rotary shaft, a rotary member, and/or a non-rotary part.